prefer Zicond primitive semantics to SFB

prefer Zicond primitive semantics to SFB

Move Zicond md files ahead of SFB to recognize Zicond first.

Take the following case for example.

CFLAGS: -mtune=sifive-7-series -march=rv64gc_zicond -mabi=lp64d

long primitiveSemantics_00(long a, long b) { return a == 0 ? 0 : b; }

before patch:
primitiveSemantics_00:
	bne	a0,zero,1f	# movcc
	mv	a1,zero
1:
	mv	a0,a1
	ret

after patch:
primitiveSemantics_00:
	czero.eqz	a0,a1,a0
	ret

Co-authored-by: Xiao Zeng<zengxiao@eswincomputing.com>
gcc/ChangeLog:

	* config/riscv/riscv.md (*mov<GPR:mode><X:mode>cc):move to sfb.md
	* config/riscv/sfb.md: New file.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/zicond-sfb-primitiveSemantics.c: New test.